Users Guide

Fabric OS Administrator’s Guide 439
53-1002920-02
Advanced bottleneck detection settings
15
Switch-wide alerting parameters:
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Alerts - Yes
Latency threshold for alert - 0.200
Congestion threshold for alert - 0.700
Averaging time for alert - 200 seconds
Quiet time for alert - 150 seconds
Adjusting the frequency of bottleneck alerts
Depending on the circumstances, a problematic switch or port may be triggering alerts more
frequently than desired. The -qtime parameter can be used to throttle alerts by specifying the
minimum number of seconds between consecutive alerts. Thresholds are configured separately for
each type of bottleneck and statistical data are collected independently for each condition.
This parameter applies individually to each type of bottleneck detection, so there can be one
latency alert and one congestion alert in one quiet time.
Example of setting quiet time
This example sets a latency threshold of 0.8 for a time window of 30 seconds, and specifies that an
alert should be sent when 80 percent (0.8) of the one-second samples over any period of 30
seconds is affected by latency bottleneck conditions; the system then waits 60 seconds before
issuing the next alert (assuming that there is one).
switch:admin> bottleneckmon --enable -lthresh 0.8 -time 30 -qtime 60
-alert=latency
Advanced bottleneck detection settings
You can use the sub-second latency criterion parameters to refine the criterion for determining
whether a second is marked as affected by latency bottlenecks. For example, you may want to use
the sub-second latency criterion parameters in the following cases:
• You notice an under-performing application, but do not see any latency bottlenecks detected.
You can temporarily increase the sub-second sensitivity of latency bottleneck detection on the
specific F_Ports for this application.
• You want greater-than-default (sub-second) latency sensitivity on your fabric, so you set
sub-second latency criterion parameters at the time you enable bottleneck detection.
• You want to reduce the number of alerts you are receiving about known latency bottlenecks in
the fabric, so you temporarily decrease the sub-second latency sensitivity on these ports.
• You have a latency bottleneck on an ISL that is not at the edge of the fabric.
The sub-second latency criterion parameters are always applicable. These parameters affect alerts
and, even if alerting is not enabled, they affect the history of bottleneck statistics.
The following sub-second latency criterion parameters are shown with the default values in
parentheses:
• -lsubsectimethresh (0.8) is similar to the -lthresh alerting parameter, except on a sub-second
level. The default value of 0.8 means that at least 80 percent of a second must be affected by
latency for the second to be marked as affected.